简介:ThispaperdealswiththetemperaturecorrelationofgrayscaleofBmodeultrasoundimagefromheatedtissue.Inthisstudy,manyin-vitrofreshpigliversareheatedinatemperaturerangefrom28℃to45℃,fromwhichaseriesofB-modeultrasonicimagesofliverswereobtained.Thegray-valueisevaluatedfromtheultrasoundimagesrespectively.Acorrelationofthemeangrayvalueoftheselectedregions(12×12pixels)inB-modeultrasonicimagesofliveranditstemperaturewaspointedout.Andtheexperimentresultsagreedtheevaluationwell.Anditispossibletomonitorthetissuetemperaturechanginginhyperthermiausingthiscorrelation.
简介:ImagegeometrydistortionisanimportanttechnicalstandardinB-modeultra-sounddiagnosissystem.ThispaperinvestigatesthecauseofimagedistortioninphasedarrayB-modeultrasounddiagnosissystem.Thefirstdistortioncauseisthedelayerrorofcompoundwavebind.Phasedarrayultrasoundtranduceriscomposedofmanyrectangleunits.Withcontrollinginspiringplustime,ultrasoundwave
简介:Anewquantitativeconceptisintroducedinthispaper,whichmaybeusedtofacilitatethemeasurementofthecontrollabilityofasubspace~subspacecontrollabilitydegree.Thentheconcreteformofthesubspacecontrollabilitydegreeofaflexiblestructureisderived,andtheerrorsofsubspacecontrollabilitydegreeanddynamicalresponsecausedbythesubstitutionofarepeatedmodesubspaceforacloselyspacedmodesubspacearediscussed.Alltheresultsshowthatthissubstitutionisrationalundersomeconditions.
简介:Asimplifiedmodalmethodtoexplaintheresonancephenomenoninguidedmoderesonance(GMR)gratingswithasymmetriccoatingsispresented.Theresonanceobservedisduetotheinteractionoftwopropagationmodesinsidethegrating.Thereflectivityspectraandelectricfielddistributionscalculatedfromthesimplifiedmodalmethodarecomparedusingrigorouscoupled-waveanalysis(RCWA).Theinfluencesofhigh-orderevanescentmodesontheresonancepeakareanalyzed.AmatrixFabry-Perot(FP)resonanceconditionisdevelopedtoevaluatetheresonancewavelength.AnexplanationfortheresonancephenomenonobservedbasedontheFPresonancephaseconditionisalsoproposedanddemonstrated.ThesimplifiedmethodprovidesclearphysicalinsightsintoGMRgratingsthatareusefulfortheanalysisofavarietyofotherresonancegratings.
简介:Threekeyfactorsarediscussed,whichaffectpositioningaccuracyofrange-rangepositioningmodeandhyperbolicpositioningmode.Basedontheerrorellipticaltheory,theexpressionsofpositioningerrorandofpositioninggeometricfactorofrange-rangepositioningmodeandhyperbolicpositioningmodearederived,andthepositioningerrorandtheblindpositioningareaoftwodifferentpositioningmodesareanalyzed.Accordingtotherequirementofnavigationarea,anoptimumpositional
简介:TheroleofthetranscriptionfactorNF-κBinshapingthecancermicroenvironmentisbecomingincreasinglyclear.InflammationalterstheactivityofenzymesthatmodulateNF-κBfunction,andcausesextensivechangesingenomicchromatinthatultimatelydrasticallyaltercell-specificgeneexpression.NF-κBregulatestheexpressionofcytokinesandadhesionfactorsthatcontrolinteractionsamongadjacentcells.Assuch,NF-κBfinetunestissuecellularcomposition,aswellastissues'interactionswiththeimmunesystem.Therefore,NF-κBchangesthecellresponsetohormonesandtocontactwithneighboringcells.ActivatingNF-κBconferstranscriptionalandphenotypicplasticitytoacellandtherebyenablesprofoundlocalchangesintissuefunctionandcomposition.ResearchsuggeststhattheregulationofNF-κBtargetgenesisspecificallyalteredincancer.SuchalterationsoccurnotonlyduetomutationsofNF-κBregulatoryproteins,butalsobecauseofchangesintheactivityofspecificproteostaticmodulesandmetabolicpathways.ThisarticledescribesthemolecularmodeofNF-κBregulationwithafewcharacteristicexamplesoftargetgenes.
简介:Inthispaper,thecapabilityofIEEE802.11bDistributedCoordinationFunction(DCF)modesupportingofConstantBitRate(CBR)andVariableBitRate(VBR)VoiceoverIP(VoIP)trafficisinvestigated.Then,thecapacityof802.11bWirelessLocalAreaNetwork(WLAN)systemcarryingvoicecallsinawiderangeofscenarios,includingvaryingdelayandpacketlossrateconstraintsisanalyzedandevaluated.BothG.711andG.729voiceencodingschemesandarangeofvoiceinter-arrivaltimeareconsidered.Theanalysesandsimulationresultsshowthatcapacityishighlysensitivetothedelaybudgetallocatedtothesumofpacketizationandwirelessnetworkdelays.Foragivenpacketlossrateconstrained,G.729isshowntohaveacapacitygreaterthanthatwhenG.711isused.ThesimulationresultsshowthatbysupportingVBRunderDCFmodethenetworkhastheapproximatelytwicemuchcapacityassupportingCBRhas,regardlessoftheencodingschemesandtheinter-arrivaltime.
简介:Powersystemhasitsindustrialstructurefeaturingbothnaturalmonopolyandcompetition,makingderegulationandre-regulationbecomethemainmelodyintheevolutionoftheregulatorysystemforpowerindustry.Consequently,itisoneofthemaintasksforpowerreformtodetermineanewandrationalregulatorymode.
简介:Wedemonstrateanall-fiberhigh-powerYb-doped1018nmfiberlaserwithaGaussian-shapedoutputbeamprofilebasedonamismatchedstructure,whichconsistsofapairofsingle-modefiberBragggratingsandasectionoffew-modedouble-claddinggainfiber.Theoutputpowerisupto107.5Wwithanoptical-to-opticalefficiencyof63%,andthe3dBbandis0.26nmatthispowerlevel.Suchastructureofsingle-mode–few-mode–single-modefiberoscillatorcanbeusedtogeneratehigh-powernarrow-linewidthlasingwithexcellentbeamqualityinotherspectralranges.
简介:ThispaperanalyzesthecharacteristicofmatchingeffciencybetweenthefundamentalmodeoftwokindsofopticalwaveguidesanditsGaussianapproximatefield.Then,itpresentsanewmethodwherethemode-fieldhalf-widthofGaussianapproximationforthefundamentalmodeshouldbedefinedaccordingtothemaximalmatchingeffciencymethod.Therelationshipbetweenthemode-fieldhalf-widthoftheGaussianapproximatefieldobtainedfromthemaximalmatchingeffciencyandnormalizedfrequencyisstudied;furthermore,twoformulasofmode-fieldhalf-widthsasafunctionofnormalizedfrequencyareproposed.
简介:Weproposeahighsensitivitysensorbasedonamodenumber-encodedmulti-longitudinalmodefiberlaser.ThefiberlaserincorporatesauniformfiberBragggrating(FBG)andafiberFabry-Perotinterferometer(FFPI)assensitivecomponentsinthecavity.Thesensorcountsthenumberoflongitudinalmodes(NLM)offiberlaser,whichiscausedbythemismatchbetweenthereflectionbandofFBGandthetransmissionbandofFFPIresultingfromtheapplicationofexternalperturbationtotheFBG.AnelectricalspectrumanalyzerisadoptedtoanalyzetheNLM.Thestrainsensorisexperimentallydemonstratedtohavesensitivityofashighas0.02με/mode.
简介:Withtherapidprogressofcomponenttechnology,thesoftwaredevelopmentmethodologyofgatheringalargenumberofcomponentsfordesigningcomplexsoftwaresystemshasmatured.But,howtoassesstheapplicationreliabilityaccuratelywiththeinformationofsystemarchitectureandthecomponentsreliabilitiestogetherhasbecomeaknottyproblem.Inthispaper,thedefectsinformaldescriptionofsoftwarearchitectureandthelimitationsinexistedmodelassumptionsarebothanalyzed.Moreover,anewsoftwarereliabilitymodelcalledComponentInteractionMode(CIM)isproposed.Withthismodel,theproblemforexistedcomponent-basedsoftwarereliabilityanalysismodelsthatcannotdealwiththecasesofcomponentinteractionwithnon-failureindependentandnon-randomcontroltransitionisresolved.Atlast,thepracticeexamplesarepresentedtoillustratetheeffectivenessofthismodel.